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<FONT color="green">001</FONT>    <a name="line.1"></a>
<FONT color="green">002</FONT>    /*<a name="line.2"></a>
<FONT color="green">003</FONT>     * Copyright (C) 2011 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<FONT color="green">004</FONT>     *<a name="line.4"></a>
<FONT color="green">005</FONT>     * $Id: AsyncOutputStream.html 75 2011-04-19 18:08:24Z archie.cobbs $<a name="line.5"></a>
<FONT color="green">006</FONT>     */<a name="line.6"></a>
<FONT color="green">007</FONT>    <a name="line.7"></a>
<FONT color="green">008</FONT>    package org.dellroad.stuff.io;<a name="line.8"></a>
<FONT color="green">009</FONT>    <a name="line.9"></a>
<FONT color="green">010</FONT>    import java.io.FilterOutputStream;<a name="line.10"></a>
<FONT color="green">011</FONT>    import java.io.IOException;<a name="line.11"></a>
<FONT color="green">012</FONT>    import java.io.OutputStream;<a name="line.12"></a>
<FONT color="green">013</FONT>    <a name="line.13"></a>
<FONT color="green">014</FONT>    import org.dellroad.stuff.java.CheckedExceptionWrapper;<a name="line.14"></a>
<FONT color="green">015</FONT>    import org.dellroad.stuff.java.Predicate;<a name="line.15"></a>
<FONT color="green">016</FONT>    import org.dellroad.stuff.java.TimedWait;<a name="line.16"></a>
<FONT color="green">017</FONT>    import org.slf4j.Logger;<a name="line.17"></a>
<FONT color="green">018</FONT>    import org.slf4j.LoggerFactory;<a name="line.18"></a>
<FONT color="green">019</FONT>    <a name="line.19"></a>
<FONT color="green">020</FONT>    /**<a name="line.20"></a>
<FONT color="green">021</FONT>     * An {@link OutputStream} that performs writes using a background thread, so that<a name="line.21"></a>
<FONT color="green">022</FONT>     * write, flush, and close operations never block.<a name="line.22"></a>
<FONT color="green">023</FONT>     * &lt;p/&gt;<a name="line.23"></a>
<FONT color="green">024</FONT>     * &lt;p&gt;<a name="line.24"></a>
<FONT color="green">025</FONT>     * If the underlying output stream throws an {@link IOException} during any operation,<a name="line.25"></a>
<FONT color="green">026</FONT>     * this instance will re-throw the exception for all subsequent operations.<a name="line.26"></a>
<FONT color="green">027</FONT>     * &lt;/p&gt;<a name="line.27"></a>
<FONT color="green">028</FONT>     * &lt;p/&gt;<a name="line.28"></a>
<FONT color="green">029</FONT>     * &lt;p&gt;<a name="line.29"></a>
<FONT color="green">030</FONT>     * Instances use an internal buffer whose size is configured at construction time;<a name="line.30"></a>
<FONT color="green">031</FONT>     * if the buffer overflows, a {@link BufferOverflowException} is thrown.<a name="line.31"></a>
<FONT color="green">032</FONT>     * &lt;/p&gt;<a name="line.32"></a>
<FONT color="green">033</FONT>     * &lt;p/&gt;<a name="line.33"></a>
<FONT color="green">034</FONT>     * &lt;p&gt;<a name="line.34"></a>
<FONT color="green">035</FONT>     * Instances of this class are thread safe, and moreover writes are atomic: if multiple threads are writing<a name="line.35"></a>
<FONT color="green">036</FONT>     * at the same time the bytes written in any single method invocation are written contiguously to the<a name="line.36"></a>
<FONT color="green">037</FONT>     * underlying output.<a name="line.37"></a>
<FONT color="green">038</FONT>     * &lt;/p&gt;<a name="line.38"></a>
<FONT color="green">039</FONT>     */<a name="line.39"></a>
<FONT color="green">040</FONT>    public class AsyncOutputStream extends FilterOutputStream {<a name="line.40"></a>
<FONT color="green">041</FONT>    <a name="line.41"></a>
<FONT color="green">042</FONT>        protected final Logger log = LoggerFactory.getLogger(getClass());<a name="line.42"></a>
<FONT color="green">043</FONT>    <a name="line.43"></a>
<FONT color="green">044</FONT>        private final String name;<a name="line.44"></a>
<FONT color="green">045</FONT>        private final byte[] buf;           // output buffer<a name="line.45"></a>
<FONT color="green">046</FONT>        private int count;                  // number of bytes in output buffer ready to be written<a name="line.46"></a>
<FONT color="green">047</FONT>        private int flushMark = -1;         // buffer byte at which a flush is requested, or -1 if none<a name="line.47"></a>
<FONT color="green">048</FONT>        private Thread thread;              // async writer thread<a name="line.48"></a>
<FONT color="green">049</FONT>        private IOException exception;      // exception caught by async thread<a name="line.49"></a>
<FONT color="green">050</FONT>        private boolean closed;             // this instance has been close()'d<a name="line.50"></a>
<FONT color="green">051</FONT>    <a name="line.51"></a>
<FONT color="green">052</FONT>        /**<a name="line.52"></a>
<FONT color="green">053</FONT>         * Constructor.<a name="line.53"></a>
<FONT color="green">054</FONT>         *<a name="line.54"></a>
<FONT color="green">055</FONT>         * @param out     underlying output stream<a name="line.55"></a>
<FONT color="green">056</FONT>         * @param bufsize maximum number of bytes we can buffer<a name="line.56"></a>
<FONT color="green">057</FONT>         * @param name    name for this instance; used to create the name of the background thread<a name="line.57"></a>
<FONT color="green">058</FONT>         */<a name="line.58"></a>
<FONT color="green">059</FONT>        public AsyncOutputStream(OutputStream out, int bufsize, String name) {<a name="line.59"></a>
<FONT color="green">060</FONT>            super(out);<a name="line.60"></a>
<FONT color="green">061</FONT>            if (out == null)<a name="line.61"></a>
<FONT color="green">062</FONT>                throw new IllegalArgumentException("null output");<a name="line.62"></a>
<FONT color="green">063</FONT>            this.name = name;<a name="line.63"></a>
<FONT color="green">064</FONT>            this.buf = new byte[bufsize];<a name="line.64"></a>
<FONT color="green">065</FONT>    <a name="line.65"></a>
<FONT color="green">066</FONT>            // Start worker thread<a name="line.66"></a>
<FONT color="green">067</FONT>            this.thread = new Thread(this.name) {<a name="line.67"></a>
<FONT color="green">068</FONT>                @Override<a name="line.68"></a>
<FONT color="green">069</FONT>                public void run() {<a name="line.69"></a>
<FONT color="green">070</FONT>                    AsyncOutputStream.this.threadMain();<a name="line.70"></a>
<FONT color="green">071</FONT>                }<a name="line.71"></a>
<FONT color="green">072</FONT>            };<a name="line.72"></a>
<FONT color="green">073</FONT>            this.thread.setDaemon(true);<a name="line.73"></a>
<FONT color="green">074</FONT>            this.thread.start();<a name="line.74"></a>
<FONT color="green">075</FONT>        }<a name="line.75"></a>
<FONT color="green">076</FONT>    <a name="line.76"></a>
<FONT color="green">077</FONT>        /**<a name="line.77"></a>
<FONT color="green">078</FONT>         * Write data.<a name="line.78"></a>
<FONT color="green">079</FONT>         *<a name="line.79"></a>
<FONT color="green">080</FONT>         * &lt;p&gt;<a name="line.80"></a>
<FONT color="green">081</FONT>         * This method will never block. To effect a normal blocking write, use {@link #waitForSpace} first.<a name="line.81"></a>
<FONT color="green">082</FONT>         * &lt;/p&gt;<a name="line.82"></a>
<FONT color="green">083</FONT>         *<a name="line.83"></a>
<FONT color="green">084</FONT>         * @param b byte to write (lower 8 bits)<a name="line.84"></a>
<FONT color="green">085</FONT>         * @throws IOException             if an exception has been thrown by the underlying stream<a name="line.85"></a>
<FONT color="green">086</FONT>         * @throws IOException             if this instance has been closed<a name="line.86"></a>
<FONT color="green">087</FONT>         * @throws BufferOverflowException if the buffer does not have room for the new byte<a name="line.87"></a>
<FONT color="green">088</FONT>         */<a name="line.88"></a>
<FONT color="green">089</FONT>        @Override<a name="line.89"></a>
<FONT color="green">090</FONT>        public void write(int b) throws IOException {<a name="line.90"></a>
<FONT color="green">091</FONT>            this.write(new byte[] { (byte)b }, 0, 1);<a name="line.91"></a>
<FONT color="green">092</FONT>        }<a name="line.92"></a>
<FONT color="green">093</FONT>    <a name="line.93"></a>
<FONT color="green">094</FONT>        /**<a name="line.94"></a>
<FONT color="green">095</FONT>         * Write data.<a name="line.95"></a>
<FONT color="green">096</FONT>         *<a name="line.96"></a>
<FONT color="green">097</FONT>         * &lt;p&gt;<a name="line.97"></a>
<FONT color="green">098</FONT>         * This method will never block. To effect a normal blocking write, invoke {@link #waitForSpace} first.<a name="line.98"></a>
<FONT color="green">099</FONT>         * &lt;/p&gt;<a name="line.99"></a>
<FONT color="green">100</FONT>         *<a name="line.100"></a>
<FONT color="green">101</FONT>         * @param data bytes to write<a name="line.101"></a>
<FONT color="green">102</FONT>         * @param off  starting offset in buffer<a name="line.102"></a>
<FONT color="green">103</FONT>         * @param len  number of bytes to write<a name="line.103"></a>
<FONT color="green">104</FONT>         * @throws IOException              if an exception has been thrown by the underlying stream<a name="line.104"></a>
<FONT color="green">105</FONT>         * @throws IOException              if this instance has been closed<a name="line.105"></a>
<FONT color="green">106</FONT>         * @throws BufferOverflowException  if the buffer does not have room for the new data<a name="line.106"></a>
<FONT color="green">107</FONT>         * @throws IllegalArgumentException if {@code len} is negative<a name="line.107"></a>
<FONT color="green">108</FONT>         */<a name="line.108"></a>
<FONT color="green">109</FONT>        @Override<a name="line.109"></a>
<FONT color="green">110</FONT>        public synchronized void write(byte[] data, int off, int len) throws IOException {<a name="line.110"></a>
<FONT color="green">111</FONT>    <a name="line.111"></a>
<FONT color="green">112</FONT>            // Check exception conditions<a name="line.112"></a>
<FONT color="green">113</FONT>            this.checkExceptions();<a name="line.113"></a>
<FONT color="green">114</FONT>            if (this.count + len &gt; this.buf.length)<a name="line.114"></a>
<FONT color="green">115</FONT>                throw new BufferOverflowException(len + " more byte(s) would exceed the " + this.buf.length + " byte buffer");<a name="line.115"></a>
<FONT color="green">116</FONT>            if (len &lt; 0)<a name="line.116"></a>
<FONT color="green">117</FONT>                throw new IllegalArgumentException("len = " + len);<a name="line.117"></a>
<FONT color="green">118</FONT>            if (len == 0)<a name="line.118"></a>
<FONT color="green">119</FONT>                return;<a name="line.119"></a>
<FONT color="green">120</FONT>    <a name="line.120"></a>
<FONT color="green">121</FONT>            // Add data to buffer<a name="line.121"></a>
<FONT color="green">122</FONT>            System.arraycopy(data, off, this.buf, this.count, len);<a name="line.122"></a>
<FONT color="green">123</FONT>            this.count += len;<a name="line.123"></a>
<FONT color="green">124</FONT>    <a name="line.124"></a>
<FONT color="green">125</FONT>            // Wakeup writer thread<a name="line.125"></a>
<FONT color="green">126</FONT>            this.notifyAll();<a name="line.126"></a>
<FONT color="green">127</FONT>        }<a name="line.127"></a>
<FONT color="green">128</FONT>    <a name="line.128"></a>
<FONT color="green">129</FONT>        /**<a name="line.129"></a>
<FONT color="green">130</FONT>         * Flush output. This method will cause the underlying stream to be flushed once all of the data written to this<a name="line.130"></a>
<FONT color="green">131</FONT>         * instance at the time this method is invoked has been written to it.<a name="line.131"></a>
<FONT color="green">132</FONT>         *<a name="line.132"></a>
<FONT color="green">133</FONT>         * &lt;p&gt;<a name="line.133"></a>
<FONT color="green">134</FONT>         * If additional data is written and then a second flush is requested before the first flush has actually occurred,<a name="line.134"></a>
<FONT color="green">135</FONT>         * the first flush will be canceled and only the second flush will be applied. Normally this is not a problem because<a name="line.135"></a>
<FONT color="green">136</FONT>         * the act of writing more data and then flushing forces earlier data to be flushed as well.<a name="line.136"></a>
<FONT color="green">137</FONT>         * &lt;/p&gt;<a name="line.137"></a>
<FONT color="green">138</FONT>         *<a name="line.138"></a>
<FONT color="green">139</FONT>         * &lt;p&gt;<a name="line.139"></a>
<FONT color="green">140</FONT>         * This method will never block. To block until the underlying flush operation completes, invoke {@link #waitForIdle}.<a name="line.140"></a>
<FONT color="green">141</FONT>         * &lt;/p&gt;<a name="line.141"></a>
<FONT color="green">142</FONT>         *<a name="line.142"></a>
<FONT color="green">143</FONT>         * @throws IOException if this instance has been closed<a name="line.143"></a>
<FONT color="green">144</FONT>         * @throws IOException if an exception has been detected on the underlying stream<a name="line.144"></a>
<FONT color="green">145</FONT>         * @throws IOException if the current thread is interrupted; the nested exception will an {@link InterruptedException}<a name="line.145"></a>
<FONT color="green">146</FONT>         */<a name="line.146"></a>
<FONT color="green">147</FONT>        @Override<a name="line.147"></a>
<FONT color="green">148</FONT>        public synchronized void flush() throws IOException {<a name="line.148"></a>
<FONT color="green">149</FONT>            this.checkExceptions();<a name="line.149"></a>
<FONT color="green">150</FONT>            this.flushMark = this.count;<a name="line.150"></a>
<FONT color="green">151</FONT>            this.notifyAll();                               // wake up writer thread<a name="line.151"></a>
<FONT color="green">152</FONT>        }<a name="line.152"></a>
<FONT color="green">153</FONT>    <a name="line.153"></a>
<FONT color="green">154</FONT>        /**<a name="line.154"></a>
<FONT color="green">155</FONT>         * Close this instance. This will (eventually) close the underlying output stream.<a name="line.155"></a>
<FONT color="green">156</FONT>         *<a name="line.156"></a>
<FONT color="green">157</FONT>         * &lt;p&gt;<a name="line.157"></a>
<FONT color="green">158</FONT>         * If this instance has already been closed, nothing happens.<a name="line.158"></a>
<FONT color="green">159</FONT>         * &lt;/p&gt;<a name="line.159"></a>
<FONT color="green">160</FONT>         *<a name="line.160"></a>
<FONT color="green">161</FONT>         * &lt;p&gt;<a name="line.161"></a>
<FONT color="green">162</FONT>         * This method will never block. To block until the underlying close operation completes, invoke {@link #waitForIdle}.<a name="line.162"></a>
<FONT color="green">163</FONT>         * &lt;/p&gt;<a name="line.163"></a>
<FONT color="green">164</FONT>         *<a name="line.164"></a>
<FONT color="green">165</FONT>         * @throws IOException if an exception has been detected on the underlying stream<a name="line.165"></a>
<FONT color="green">166</FONT>         */<a name="line.166"></a>
<FONT color="green">167</FONT>        @Override<a name="line.167"></a>
<FONT color="green">168</FONT>        public synchronized void close() throws IOException {<a name="line.168"></a>
<FONT color="green">169</FONT>            if (this.closed)<a name="line.169"></a>
<FONT color="green">170</FONT>                return;<a name="line.170"></a>
<FONT color="green">171</FONT>            this.closed = true;<a name="line.171"></a>
<FONT color="green">172</FONT>            this.notifyAll();                               // wake up writer thread<a name="line.172"></a>
<FONT color="green">173</FONT>        }<a name="line.173"></a>
<FONT color="green">174</FONT>    <a name="line.174"></a>
<FONT color="green">175</FONT>        /**<a name="line.175"></a>
<FONT color="green">176</FONT>         * Get the exception thrown by the underlying output stream, if any.<a name="line.176"></a>
<FONT color="green">177</FONT>         *<a name="line.177"></a>
<FONT color="green">178</FONT>         * @return thrown exception, or {@code null} if none has been thrown by the underlying stream<a name="line.178"></a>
<FONT color="green">179</FONT>         */<a name="line.179"></a>
<FONT color="green">180</FONT>        public synchronized IOException getException() {<a name="line.180"></a>
<FONT color="green">181</FONT>            return this.exception;<a name="line.181"></a>
<FONT color="green">182</FONT>        }<a name="line.182"></a>
<FONT color="green">183</FONT>    <a name="line.183"></a>
<FONT color="green">184</FONT>        /**<a name="line.184"></a>
<FONT color="green">185</FONT>         * Get the capacity of this instance's output buffer.<a name="line.185"></a>
<FONT color="green">186</FONT>         *<a name="line.186"></a>
<FONT color="green">187</FONT>         * @return output buffer capacity configured at construction time<a name="line.187"></a>
<FONT color="green">188</FONT>         */<a name="line.188"></a>
<FONT color="green">189</FONT>        public synchronized int getBufferSize() {<a name="line.189"></a>
<FONT color="green">190</FONT>            return this.buf.length;<a name="line.190"></a>
<FONT color="green">191</FONT>        }<a name="line.191"></a>
<FONT color="green">192</FONT>    <a name="line.192"></a>
<FONT color="green">193</FONT>        /**<a name="line.193"></a>
<FONT color="green">194</FONT>         * Get the number of free bytes remaining in the output buffer.<a name="line.194"></a>
<FONT color="green">195</FONT>         *<a name="line.195"></a>
<FONT color="green">196</FONT>         * @return current number of available bytes in the output buffer<a name="line.196"></a>
<FONT color="green">197</FONT>         * @throws IOException              if this instance is or has been closed<a name="line.197"></a>
<FONT color="green">198</FONT>         * @throws IOException              if an exception has been detected on the underlying stream<a name="line.198"></a>
<FONT color="green">199</FONT>         * @see #waitForSpace<a name="line.199"></a>
<FONT color="green">200</FONT>         */<a name="line.200"></a>
<FONT color="green">201</FONT>        public synchronized int availableBufferSpace() throws IOException {<a name="line.201"></a>
<FONT color="green">202</FONT>            this.checkExceptions();<a name="line.202"></a>
<FONT color="green">203</FONT>            return this.buf.length - this.count;<a name="line.203"></a>
<FONT color="green">204</FONT>        }<a name="line.204"></a>
<FONT color="green">205</FONT>    <a name="line.205"></a>
<FONT color="green">206</FONT>        /**<a name="line.206"></a>
<FONT color="green">207</FONT>         * Determine if there is outstanding work still to be performed (writes, flushes, and/or close operations)<a name="line.207"></a>
<FONT color="green">208</FONT>         * by the background thread.<a name="line.208"></a>
<FONT color="green">209</FONT>         *<a name="line.209"></a>
<FONT color="green">210</FONT>         * @throws IOException              if this instance is or has been closed<a name="line.210"></a>
<FONT color="green">211</FONT>         * @throws IOException              if an exception has been detected on the underlying stream<a name="line.211"></a>
<FONT color="green">212</FONT>         * @see #waitForIdle<a name="line.212"></a>
<FONT color="green">213</FONT>         */<a name="line.213"></a>
<FONT color="green">214</FONT>        public synchronized boolean isWorkOutstanding() throws IOException {<a name="line.214"></a>
<FONT color="green">215</FONT>            this.checkExceptions();<a name="line.215"></a>
<FONT color="green">216</FONT>            return this.threadHasWork();<a name="line.216"></a>
<FONT color="green">217</FONT>        }<a name="line.217"></a>
<FONT color="green">218</FONT>    <a name="line.218"></a>
<FONT color="green">219</FONT>        /**<a name="line.219"></a>
<FONT color="green">220</FONT>         * Wait for buffer space availability.<a name="line.220"></a>
<FONT color="green">221</FONT>         *<a name="line.221"></a>
<FONT color="green">222</FONT>         * @param numBytes amount of buffer space required<a name="line.222"></a>
<FONT color="green">223</FONT>         * @param timeout  maximum time to wait in milliseconds, or zero for infinite<a name="line.223"></a>
<FONT color="green">224</FONT>         * @return true if space was found, false if time expired<a name="line.224"></a>
<FONT color="green">225</FONT>         * @throws IOException              if this instance is or has been closed<a name="line.225"></a>
<FONT color="green">226</FONT>         * @throws IOException              if an exception has been detected on the underlying stream<a name="line.226"></a>
<FONT color="green">227</FONT>         * @throws IllegalArgumentException if {@code numBytes} is greater than the configured buffer size<a name="line.227"></a>
<FONT color="green">228</FONT>         * @throws IllegalArgumentException if {@code timeout} is negative<a name="line.228"></a>
<FONT color="green">229</FONT>         * @throws InterruptedException     if the current thread is interrupted<a name="line.229"></a>
<FONT color="green">230</FONT>         * @see #availableBufferSpace<a name="line.230"></a>
<FONT color="green">231</FONT>         */<a name="line.231"></a>
<FONT color="green">232</FONT>        public boolean waitForSpace(final int numBytes, long timeout) throws IOException, InterruptedException {<a name="line.232"></a>
<FONT color="green">233</FONT>            if (numBytes &gt; this.buf.length)<a name="line.233"></a>
<FONT color="green">234</FONT>                throw new IllegalArgumentException("numBytes (" + numBytes + ") &gt; buffer size (" + this.buf.length + ")");<a name="line.234"></a>
<FONT color="green">235</FONT>            return this.waitForPredicate(timeout, new Predicate() {<a name="line.235"></a>
<FONT color="green">236</FONT>                @Override<a name="line.236"></a>
<FONT color="green">237</FONT>                public boolean test() {<a name="line.237"></a>
<FONT color="green">238</FONT>                    return AsyncOutputStream.this.buf.length - AsyncOutputStream.this.count &gt;= numBytes;<a name="line.238"></a>
<FONT color="green">239</FONT>                }<a name="line.239"></a>
<FONT color="green">240</FONT>            });<a name="line.240"></a>
<FONT color="green">241</FONT>        }<a name="line.241"></a>
<FONT color="green">242</FONT>    <a name="line.242"></a>
<FONT color="green">243</FONT>        /**<a name="line.243"></a>
<FONT color="green">244</FONT>         * Wait for all outstanding work to complete.<a name="line.244"></a>
<FONT color="green">245</FONT>         *<a name="line.245"></a>
<FONT color="green">246</FONT>         * @param timeout maximum time to wait in milliseconds, or zero for infinite<a name="line.246"></a>
<FONT color="green">247</FONT>         * @return true for success, false if time expired<a name="line.247"></a>
<FONT color="green">248</FONT>         * @throws IOException              if this instance is or has been closed<a name="line.248"></a>
<FONT color="green">249</FONT>         * @throws IOException              if an exception has been detected on the underlying stream<a name="line.249"></a>
<FONT color="green">250</FONT>         * @throws IllegalArgumentException if {@code timeout} is negative<a name="line.250"></a>
<FONT color="green">251</FONT>         * @throws InterruptedException     if the current thread is interrupted<a name="line.251"></a>
<FONT color="green">252</FONT>         * @see #isWorkOutstanding<a name="line.252"></a>
<FONT color="green">253</FONT>         */<a name="line.253"></a>
<FONT color="green">254</FONT>        public synchronized boolean waitForIdle(long timeout) throws IOException, InterruptedException {<a name="line.254"></a>
<FONT color="green">255</FONT>            return this.waitForPredicate(timeout, new Predicate() {<a name="line.255"></a>
<FONT color="green">256</FONT>                @Override<a name="line.256"></a>
<FONT color="green">257</FONT>                public boolean test() {<a name="line.257"></a>
<FONT color="green">258</FONT>                    return !AsyncOutputStream.this.threadHasWork();<a name="line.258"></a>
<FONT color="green">259</FONT>                }<a name="line.259"></a>
<FONT color="green">260</FONT>            });<a name="line.260"></a>
<FONT color="green">261</FONT>        }<a name="line.261"></a>
<FONT color="green">262</FONT>    <a name="line.262"></a>
<FONT color="green">263</FONT>        /**<a name="line.263"></a>
<FONT color="green">264</FONT>         * Check for exceptions.<a name="line.264"></a>
<FONT color="green">265</FONT>         *<a name="line.265"></a>
<FONT color="green">266</FONT>         * @throws IOException if this instance has been closed<a name="line.266"></a>
<FONT color="green">267</FONT>         * @throws IOException if an exception has been detected on the underlying stream<a name="line.267"></a>
<FONT color="green">268</FONT>         */<a name="line.268"></a>
<FONT color="green">269</FONT>        private void checkExceptions() throws IOException {<a name="line.269"></a>
<FONT color="green">270</FONT>            if (this.closed)<a name="line.270"></a>
<FONT color="green">271</FONT>                throw new IOException("instance has been closed");<a name="line.271"></a>
<FONT color="green">272</FONT>            if (this.exception != null)<a name="line.272"></a>
<FONT color="green">273</FONT>                throw new IOException("exception from underlying output stream", this.exception);<a name="line.273"></a>
<FONT color="green">274</FONT>        }<a name="line.274"></a>
<FONT color="green">275</FONT>    <a name="line.275"></a>
<FONT color="green">276</FONT>        /**<a name="line.276"></a>
<FONT color="green">277</FONT>         * Determine if there is outstanding work still to be performed (writes, flushes, and/or close operations)<a name="line.277"></a>
<FONT color="green">278</FONT>         * by the background thread.<a name="line.278"></a>
<FONT color="green">279</FONT>         */<a name="line.279"></a>
<FONT color="green">280</FONT>        private boolean threadHasWork() {<a name="line.280"></a>
<FONT color="green">281</FONT>            return this.count &gt; 0 || this.flushMark != -1 || this.closed;<a name="line.281"></a>
<FONT color="green">282</FONT>        }<a name="line.282"></a>
<FONT color="green">283</FONT>    <a name="line.283"></a>
<FONT color="green">284</FONT>        /**<a name="line.284"></a>
<FONT color="green">285</FONT>         * Writer thread main entry point.<a name="line.285"></a>
<FONT color="green">286</FONT>         */<a name="line.286"></a>
<FONT color="green">287</FONT>        private void threadMain() {<a name="line.287"></a>
<FONT color="green">288</FONT>            try {<a name="line.288"></a>
<FONT color="green">289</FONT>                this.runLoop();<a name="line.289"></a>
<FONT color="green">290</FONT>            } catch (Throwable t) {<a name="line.290"></a>
<FONT color="green">291</FONT>                synchronized (this) {<a name="line.291"></a>
<FONT color="green">292</FONT>                    this.exception = t instanceof IOException ? (IOException)t : new IOException("caught unexpected exception", t);<a name="line.292"></a>
<FONT color="green">293</FONT>                    this.notifyAll();                       // wake up sleepers in waitForSpace() and waitForIdle()<a name="line.293"></a>
<FONT color="green">294</FONT>                }<a name="line.294"></a>
<FONT color="green">295</FONT>            } finally {<a name="line.295"></a>
<FONT color="green">296</FONT>                synchronized (this) {<a name="line.296"></a>
<FONT color="green">297</FONT>                    this.thread = null;<a name="line.297"></a>
<FONT color="green">298</FONT>                    this.notifyAll();                       // wake up sleepers in waitForIdle()<a name="line.298"></a>
<FONT color="green">299</FONT>                }<a name="line.299"></a>
<FONT color="green">300</FONT>            }<a name="line.300"></a>
<FONT color="green">301</FONT>        }<a name="line.301"></a>
<FONT color="green">302</FONT>    <a name="line.302"></a>
<FONT color="green">303</FONT>        /**<a name="line.303"></a>
<FONT color="green">304</FONT>         * Async writer thread main loop.<a name="line.304"></a>
<FONT color="green">305</FONT>         */<a name="line.305"></a>
<FONT color="green">306</FONT>        private void runLoop() throws IOException, InterruptedException {<a name="line.306"></a>
<FONT color="green">307</FONT>            while (true) {<a name="line.307"></a>
<FONT color="green">308</FONT>    <a name="line.308"></a>
<FONT color="green">309</FONT>                // Wait for something to do<a name="line.309"></a>
<FONT color="green">310</FONT>                synchronized (this) {<a name="line.310"></a>
<FONT color="green">311</FONT>                    while (!this.threadHasWork())<a name="line.311"></a>
<FONT color="green">312</FONT>                        this.wait();                        // will be woken up by write(), flush(), or close()<a name="line.312"></a>
<FONT color="green">313</FONT>                }<a name="line.313"></a>
<FONT color="green">314</FONT>    <a name="line.314"></a>
<FONT color="green">315</FONT>                // Determine what needs to be done<a name="line.315"></a>
<FONT color="green">316</FONT>                int wlen;<a name="line.316"></a>
<FONT color="green">317</FONT>                boolean flush;<a name="line.317"></a>
<FONT color="green">318</FONT>                boolean close;<a name="line.318"></a>
<FONT color="green">319</FONT>                synchronized (this) {<a name="line.319"></a>
<FONT color="green">320</FONT>                    wlen = this.count;<a name="line.320"></a>
<FONT color="green">321</FONT>                    flush = this.flushMark == 0;<a name="line.321"></a>
<FONT color="green">322</FONT>                    close = this.closed;<a name="line.322"></a>
<FONT color="green">323</FONT>                }<a name="line.323"></a>
<FONT color="green">324</FONT>    <a name="line.324"></a>
<FONT color="green">325</FONT>                // First priority: any data to write?<a name="line.325"></a>
<FONT color="green">326</FONT>                if (wlen &gt; 0) {<a name="line.326"></a>
<FONT color="green">327</FONT>    <a name="line.327"></a>
<FONT color="green">328</FONT>                    // Write data<a name="line.328"></a>
<FONT color="green">329</FONT>                    this.out.write(this.buf, 0, wlen);<a name="line.329"></a>
<FONT color="green">330</FONT>    <a name="line.330"></a>
<FONT color="green">331</FONT>                    // Shift data in buffer<a name="line.331"></a>
<FONT color="green">332</FONT>                    synchronized (this) {<a name="line.332"></a>
<FONT color="green">333</FONT>                        System.arraycopy(this.buf, wlen, this.buf, 0, this.count - wlen);<a name="line.333"></a>
<FONT color="green">334</FONT>                        this.count -= wlen;<a name="line.334"></a>
<FONT color="green">335</FONT>                        if (this.flushMark != -1)<a name="line.335"></a>
<FONT color="green">336</FONT>                            this.flushMark = Math.max(0, this.flushMark - wlen);<a name="line.336"></a>
<FONT color="green">337</FONT>                        this.notifyAll();                   // wake up sleepers in waitForSpace() and waitForIdle()<a name="line.337"></a>
<FONT color="green">338</FONT>                    }<a name="line.338"></a>
<FONT color="green">339</FONT>                    continue;<a name="line.339"></a>
<FONT color="green">340</FONT>                }<a name="line.340"></a>
<FONT color="green">341</FONT>    <a name="line.341"></a>
<FONT color="green">342</FONT>                // Second priority: is a flush required?<a name="line.342"></a>
<FONT color="green">343</FONT>                if (flush) {<a name="line.343"></a>
<FONT color="green">344</FONT>    <a name="line.344"></a>
<FONT color="green">345</FONT>                    // Flush output<a name="line.345"></a>
<FONT color="green">346</FONT>                    this.out.flush();<a name="line.346"></a>
<FONT color="green">347</FONT>    <a name="line.347"></a>
<FONT color="green">348</FONT>                    // Update flush mark<a name="line.348"></a>
<FONT color="green">349</FONT>                    synchronized (this) {<a name="line.349"></a>
<FONT color="green">350</FONT>                        if (this.flushMark == 0) {<a name="line.350"></a>
<FONT color="green">351</FONT>                            this.flushMark = -1;<a name="line.351"></a>
<FONT color="green">352</FONT>                            this.notifyAll();               // wake up sleepers in waitForIdle()<a name="line.352"></a>
<FONT color="green">353</FONT>                        }<a name="line.353"></a>
<FONT color="green">354</FONT>                    }<a name="line.354"></a>
<FONT color="green">355</FONT>                    continue;<a name="line.355"></a>
<FONT color="green">356</FONT>                }<a name="line.356"></a>
<FONT color="green">357</FONT>    <a name="line.357"></a>
<FONT color="green">358</FONT>                // Third priority:  is a close required?<a name="line.358"></a>
<FONT color="green">359</FONT>                if (close) {<a name="line.359"></a>
<FONT color="green">360</FONT>                    this.out.close();<a name="line.360"></a>
<FONT color="green">361</FONT>                    break;<a name="line.361"></a>
<FONT color="green">362</FONT>                }<a name="line.362"></a>
<FONT color="green">363</FONT>            }<a name="line.363"></a>
<FONT color="green">364</FONT>        }<a name="line.364"></a>
<FONT color="green">365</FONT>    <a name="line.365"></a>
<FONT color="green">366</FONT>        /**<a name="line.366"></a>
<FONT color="green">367</FONT>         * Wait for some condition to become true. Of course somebody has to wake us up when it becomes true.<a name="line.367"></a>
<FONT color="green">368</FONT>         */<a name="line.368"></a>
<FONT color="green">369</FONT>        private synchronized boolean waitForPredicate(long timeout, final Predicate predicate)<a name="line.369"></a>
<FONT color="green">370</FONT>          throws IOException, InterruptedException {<a name="line.370"></a>
<FONT color="green">371</FONT>            try {<a name="line.371"></a>
<FONT color="green">372</FONT>                return TimedWait.wait(this, timeout, new Predicate() {<a name="line.372"></a>
<FONT color="green">373</FONT>                    @Override<a name="line.373"></a>
<FONT color="green">374</FONT>                    public boolean test() {<a name="line.374"></a>
<FONT color="green">375</FONT>                        try {<a name="line.375"></a>
<FONT color="green">376</FONT>                            checkExceptions();<a name="line.376"></a>
<FONT color="green">377</FONT>                        } catch (IOException e) {<a name="line.377"></a>
<FONT color="green">378</FONT>                            throw new CheckedExceptionWrapper(e);<a name="line.378"></a>
<FONT color="green">379</FONT>                        }<a name="line.379"></a>
<FONT color="green">380</FONT>                        return predicate.test();<a name="line.380"></a>
<FONT color="green">381</FONT>                    }<a name="line.381"></a>
<FONT color="green">382</FONT>                });<a name="line.382"></a>
<FONT color="green">383</FONT>            } catch (CheckedExceptionWrapper e) {<a name="line.383"></a>
<FONT color="green">384</FONT>                throw (IOException)e.getException();<a name="line.384"></a>
<FONT color="green">385</FONT>            }<a name="line.385"></a>
<FONT color="green">386</FONT>        }<a name="line.386"></a>
<FONT color="green">387</FONT>    }<a name="line.387"></a>
<FONT color="green">388</FONT>    <a name="line.388"></a>




























































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